Alternating-current welding system



O. H.' ESCHHOLZ.

ALTERNATING CURRENT WELDING SYSTEM.

APPLICATION FILED JUNE 25.!919.

1,365,531 1 Patented Jan. H, 1921.

WITNESSES: INVENTOR ATTORNEY cure a. seesaw,

SYLVAE'IA,

PENNQYLVANTZA, ASSIGNOR HOUSE ELECTRIC 85 BIAJIUFAUTUBING GGMPANY, A

JG WESTING- CGRPORAT, )N @F PENN- ghIfIlEREZATIhlG-UZFEEEN E fVIELDIll'E-l- SYSTEM.

Specification of Letters Eater-it.

Patented Jan. ll, 192 i,

hwl'leatlon filed rune 1 .9. Serial No. 308,520.

To all whom it may concern primary object of my invention is to provide' a system which shall facilitate. weldmg by means of alternatingcurrent and, at the same time, insure satisfactory results.

,Nhile it has been found practicable to maintain a Welding-arc by meansof a 110- volt, 60-cycle alternating current, when eniploying a seriesballast resistance of actance, difficulty has been encountered instartin the arc unless a high are current was utilized. A higharccurrent is necessary in establishing an are on account oi? the factthat the Work must be materially heated before an arc can be drawn. Asuitable cur rent value for starting the are, if maintained, wouldresult in an excessive rate of deposition of metal or melting throughthe parent metal of the scarf. In view of this,

one object of my invention is to provide a Welding system in Whichasuitable start ing current may be employed and a desirable operatingcurrent automatically established after an arc has been drawn.

A still further object of my invention is to provide an arc Weldingsystem in which :a high starting current value may obtill tained and asubsequent desirable operating current value be automaticallyestal'iiished Without the employment, and consequent complication, ofmovable parts.

With these and other objects in view, my invention Will be more fullydescribed, illustrated in the drawing, in which con" spending numeralsindicate like parts, and then narticularly pointed'out in the claims.

in the single figure oi the drawing, an arc ,welding circuit isdia'grammatically shown which embodies my invention.

In practising my invention 1 may employ a Welding system, such as shownin the drawing, comprising a primary winding 1, which may be connectedto a suitable source of alternating current, (not shown) and a secondaryWinding 2 which is, of course. inductively related to the primarywinding. (hie side oi the inding 2 may be connected to a weldingelectrode 3 and the oth side may be connected, through an inductance land a resistance 5, to another electrode 6. may employ an additionalWinding 7 jvhich is also inductively related to the pri- 'niary winding1 and which may be connected, at one side, to the electrode 6 and, atits other side, through an inductance S, to the other electrode 3.

in operation, the above described Welding system may be energized byconnecting the primary winding), 1 to a suitablesource of alternatingcurrent supply. The secondary winding 2 will, therefore, be energized,and, when the electrodes 3 and 6 are engaged, a current will flowthrough the circuit thus established, the main Welding circuitcomprising the secondary winding 2, the inductance a, the resistance 5,and the electrodes 3 and 6. fl hen the electrodes are engaged and thenslowly drawn apart, an arc may be drawn in the ordinary manner..ll'owever, when the electrodes engage, a lowresistance path providedthrough ,ivhieh the additional Winding 7 tends to send a relativelyheavy current. The current thus supplied may be of any desired valueaccord ing to the design of the Winding 7. Fur thermore, the coil 7 isso connected that the current supplied by it to the main Welding;circuit will add to the current in the main Welding circuit and thusgreatly increase the starting current. r

The value of the current passing through the additional coil '7, underboth open-circuit and closed-circuit conditions, -may be so regulated bythe design or". the coil as to,

greatly facilitate starting the are. llhe in1- pedauec in the mainWelding circuit, represented by the inductance i and the resistance o, 1employed to stabilize the are and faciliin holding" a steady are underop 'ating co. a. The inductance 8, in so ics with the adcitional coil 7,also acts as asj jabilinii"ig means and limits the flow' of current, Thevoltage maintained between the electrodes,

under open-circuit conditions, may range from 10 volts to 130 volts and,when an arc is burning, the voltage drop is between 15 and 20 volts.

The valu of employing means for increasing the value of the startingcurrent is materially greater when utilizing welding currents ofrelatively small value, as such currents do not heat the work (prickly,and, consequently, cause starting ditliculties. It will be appreciatedthat, by employing an additional winding to increase the shortcireuitvalue of current in the welding system, the operation of starting an arcis greatly facilitated and this result is accomplished by employing asimple system which is not subject to disorders encountered in apparatushaving relatively movable parts. The system above described wouldordinarily be designed to effect a 50% increase in the value of thecurrent during the starting period or When the electrodes are engaged.

Although I have specifically described a welding system which may beemployed in accordance with my invention, it is obvious that minorchanges may be made in the arrangement and construction thereof and Idesire, therefore, that no limitations shall be imposed except such asare indicated in the appended claims.

I claim as my invention 1. An arc welding system comprising a primaryWinding, a secondary Winding, a plurality of electrodes connected to thesec ondary winding, and an additional Winding inductively related to theprimary winding connected in parallel relation to the eleetrodes 2. Anarc welding; system comprising a primary winding, a secondary winding,an impedance connected to said secondary Wind-- ing, a pluralit-iy ofelectrodes connected to the secondary winding and in series with theimpedance, and an additional ind b inductively related to the primary viinding connected to the electrodes.

3. An arc welding system comprising a primary winding, a secondarywinding, an impedance connected to said secondary winding, a pluralityof electrodes connected to the secondary winding and in series with theimpedance, an additional winding inductively related to the primaryWinding connected to the electrodes, and an impedance connected inseries with the additional Wind in;' and the electrodes.

In testimony whereof, I have hereunto subscribed my name this 19th dayof June o'r'ro H. ESCHHOLZ.

